Oxidation reactions of alcohols to carbonyl compounds represent one of the most fundamental reactions used for the organic syntheses of high value-added compounds such as medicaments, agricultural chemicals, flavoring ingredients, and chemical products. For this reason, many techniques have been developed in the past years. However, many of these methods involve use of toxic and explosive oxidizing agents, or require extremely low temperatures of −40 degrees or less. Over these backgrounds, a technique that uses 2,2,6,6-tetramethylpiperidine 1-oxyl (hereinafter also referred to as “TEMPO”) has attracted interest as a method that permits large-scale oxidation by taking advantage of the ability of this catalyst to oxidize alcohol even under very mild conditions of from 0 degree to room temperature using various co-oxidizing agents without using high toxicity reagents. It has been reported that many oxidizing agents have potential use as co-oxidizing agents (Non Patent Literature 3), including, for example, a low-cost and environmentally friendly sodium hypochlorite aqueous solution used in industrial and other processes (Non Patent Literature 1), iodobenzenediacetate (PhI(OAc)2) that can coexist with a wide range of functional groups even in applications that use alcohols having double bonds and electron-rich aromatic rings (Non Patent Literature 2), and a molecular oxygen having high safety and high atom efficiency. The present inventors have reported that a nitroxyl radical having an azaadamantane skeleton (2-azaadamantane N-oxyl (hereinafter, also referred to as “AZADO”), and 1-methyl-2-azaadamantane N-oxyl (hereinafter, also referred to as “1-Me-AZADO”)), a nitroxyl radical having an azabicyclo[3.3.1]nonane skeleton (9-azabicyclo[3.3.1]nonane N-oxyl), and 9-azanoradamantane N-oxyl having an azanoradamantane skeleton (hereinafter, also referred to as “Nor-AZADO”) have higher catalytic activity than TEMPO, and promote a fast oxidation of bulky secondary alcohols that cannot be oxidized with TEMPO (Non Patent Literatures 4, 5, 6, 7, 8, and Patent Literatures 1, 2, 3, 4, and 5).
In oxidation reactions catalyzed by TEMPO, reaction that selectively oxidizes primary alcohols proceeds with a substrate that includes both primary alcohol and secondary alcohol (Non Patent Literature 9). Such selective oxidation of a specific alcohol is important as an alternative method of distinguishing a functional group in the synthesis of polyfunctional compounds commonly distinguished and synthesized with a protecting group. Such a reaction is also important because it can contribute to simplifying the synthesis process with the single step of alcohol oxidation reaction, as opposed to using a protecting group that requires protecting and deprotecting steps. In fact, there are many reports of synthesizing natural products using such reactions.